Increased stress tolerance, yield, and quality via glutaredoxin overexpression

Abstract

Oxygenic photosynthesis is the major site of production of reactive oxygen species (ROS). Under high temperature stress, increased ROS damage the photosynthetic machinery, membranes and proteins of plants. The present invention is directed to methods for increasing the stress tolerance of plants by expressing PvGrx5 in the plants.

The invention claimed is: 
     
       1. A method for increasing drought or high temperature stress tolerance in a plant and for reducing oxidative damage to plant proteins of the plant comprising expressing a heterologous nucleic acid encoding the amino acid sequence set forth in SEQ ID NO: 2 encoding PvGrx5 in the plant and selecting for plants that exhibit an increased tolerance to high temperature or drought stress compared to the plant without the heterologous nucleic acid when the plants are grown under the same conditions. 
     
     
       2. The method of  claim 1 , wherein expressing said heterologous nucleic acid increases the biomass and/or grain yield of said plant compared to the plant without the heterologous nucleic acid when the plants are grown under the same conditions. 
     
     
       3. A plant comprising a plurality of cells expressing the heterologous nucleic acid of  claim 1 . 
     
     
       4. A method of producing the PvGrx5 protein set forth in SEQ ID NO: 2 comprising culturing host cells that have been transformed with a nucleic acid encoding the PvGrx5 under conditions in which the PvGrx5 is expressed and isolating the PvGrx5. 
     
     
       5. The method of  claim 1 , further comprising producing a parent transgenic plant expressing a heterologous nucleic acid sequence encoding PvGrx5; isolating seeds from the parent transgenic plant; growing transgenic progeny plants from said seeds that comprise the nucleic acid sequence encoding PvGrx5; and selecting for a transgenic progeny plant comprising the heterologous nucleic acid that has a heat or drought stress tolerant phenotype and has a biomass greater than that of a plant having no expression of said nucleic acid sequence under heat or drought conditions.